Previous attempts to remove a plume of liquid contamination contained below ground have included placement of numerous vertical wells placed around the periphery of the plume. The vertical wells are operated continuously in an attempt to draw the liquid of a contamination plume towards the vertical well system. Great amounts of water are pumped out of the ground by these vertical wells at a great cost and over an extended period of time.
These plumes of liquid are known to contain such dangerous substances as diesel fuel, jet fuel, gasoline, heating oil, creosote, and other chemicals, for example. Sources of contamination are thousands of aging underground tanks buried beneath schools, government offices, gasoline stations, businesses and abandoned property distributed throughout the United States. This problem has often times resulted in homeowners being forced from their homes due to condemning of their homes by public officials due to the extreme hazard and health risks involved.
The presence of these contaminants in the water table present a continuous potential health hazard to the population. Rural and suburban residents who use wells for the source of their drinking water are particularly affected by this problem. It is estimated that half of the country relies on this type of source for their drinking water. The removal of these contaminants is therefore required to help ensure a potable water supply.
In 1988, the Environmental Protection Agency (EPA) issued regulations requiring that new underground tanks meet minimum standards. Owners of older tanks were forced to close or upgrade their tanks. Since these regulations have been implemented, 130,000 leaks have been documented. Experts expect hundreds of thousands of more leaks to be discovered in the future. The new EPA rules have been estimated to apply to 1.8 million tanks nationwide. This number excludes millions of home heating oil, farm and other smaller underground tanks potentially subject to producing leaks.